French Associates Institutes for Agriculture and Biotechnology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 84990, Israel.
Department of Physics, Indian Institute of Technology Bombay, Mumbai, 400076, India.
Sci Rep. 2022 Jun 10;12(1):9635. doi: 10.1038/s41598-022-14093-1.
Arabidopsis roots grown on inclined agar surfaces exhibit unusual sinusoidal patterns known as root-waving. The origin of these patterns has been ascribed to both genetic and environmental factors. Here we propose a mechano-sensing model for root-waving, based on a combination of friction induced by gravitropism, the elasticity of the root and the anchoring of the root to the agar by thin hairs, and demonstrate its relevance to previously obtained experimental results. We further test the applicability of this model by performing experiments in which we measure the effect of gradually changing the inclination angles of the agar surfaces on the wavelength and other properties of the growing roots. We find that the observed dynamics is different than the dynamics reported in previous works, but that it can still be explained using the same mechano-sensing considerations. This is supported by the fact that a scaling relation derived from the model describes the observed dependence of the wavelength on the tilt angle for a large range of angles. We also compare the prevalence of waving in different plant species and show that it depends on root thickness as predicted by the model. The results indicate that waving can be explained using mechanics and gravitropism alone and that mechanics may play a greater role in root growth and form than was previously considered.
在倾斜琼脂表面上生长的拟南芥根表现出一种不寻常的正弦波图案，称为根波。这些图案的起源归因于遗传和环境因素。在这里，我们提出了一种基于向重性引起的摩擦、根的弹性以及根与琼脂通过细毛的锚定的根波的机械感应模型，并证明了它与先前获得的实验结果的相关性。我们通过进行实验进一步测试了该模型的适用性，在实验中，我们测量了逐渐改变琼脂表面倾斜角度对生长中根的波长和其他性质的影响。我们发现，观察到的动力学与以前的工作中报道的动力学不同，但仍可以使用相同的机械感应考虑来解释。这一事实得到了支持，即模型推导出的标度关系描述了在很大角度范围内观察到的波长对倾斜角的依赖性。我们还比较了不同植物物种中出现的波动情况，并表明它如模型所预测的那样取决于根的厚度。结果表明，仅使用力学和向重性就可以解释波动，并且力学在根的生长和形态中可能发挥比以前认为的更大的作用。
